Servo pressure regulator valve



Oct. 16, 1951 J. MERCIER 2,571,154

SERVO PRESSURE REGULATOR VALVE Filed Oct. so, 1944 =Fi l INVENTOR. Jean Meraer Z, ATTORNEY Patented Oct. 16, 1951 U N I T ED" STAT ES Nil" F lC E SERVO PRESSURE REGUHATOR 'VALVE Jean Mercicr, New.-York,. N.' Y.. 7

Application October 30, 1944;1'Serial No;,560,'998

(Cl. ISL-53) L-Glaim: 1

My invention. relates to :unloader. valves for servo-pressure regulators. I

One-object of the invention is to produce iunleader valves which open" and close with'great precision" under elimination 10f all mechanical friction.

Another objector the invention is toiproduce unloader valves which"are' operated exclusively bythe pressure in the-supplydine' ,but which are controlled by the pressureintheutilization,line so that while the mainvalve and" the pilot valve are-opened and" kept" open", thetpressure; in the utilization line may remain unchanged at'its maximum value. thusspermittin'g' ithe omission of the hydraulic accumulator, if desired,

vI accomplish this and other objects whichwill appear more clearly as the specification proceeds, by the arrangement and combination of parts and elements set forth in the following detailed description, defined in the appended claim and illustratively exemplified in the accompanying drawings, in which Figs. 1 and 2 are sectional views of two embodiments of an unloader valve construction according to the invention.

Referring now to the drawings, in Fig. 1 the valve comprises a casing with three ports, that is, the supply port 46, the return port 41, and the utilization port 48. A check valve 49 prevents back flow from the utilization port 48 to the supply port 46.

The principal valve means include a seat 50, a main valve body 5| having a plunger portion 5|, a plunger chamber 52, and a spring 62.

The pilot valve means include a tubular pilot valve chamber 54 provided in the pilot casing 45 at right angles to the axis of the main valve and opening at one end into the utilization port 48 rearwardly of the check valve 49, and at its other end into a space which communicates through a passage 6% with the exhaust port 41. A pilot valve seat 54 is formed at said other end of the pilot valve chamber 54. A pilot valve 5'! is urged against said pilot valve seat 54 from the outside by means of a plunger 58 loaded by a spring 53. At its end opening into the utilization port 48 the pilot valve chamber 54 is provided with an auxiliary valve seat 54 An elongated rod 55 rests with its lower end on the pilot valve 51 and. traverses the pilot valve chamber 54 in axial direction with considerable clearance, and is provided at its end adjacent the auxiliary valve seat 54 with a piston-like portion 55, which normally projects slightly from the valve seat 54. An auxiliary'valve body thei-passage fill and the pilot valve chamber 54;

As longxthe pressure in. this -chamber=-'is -belowi-thepredetermined limit; the pilot valve:5'|1 andzthe main .valve 5 I remain closed. Whenthepressure intthe. inlet port 46.7and" utilization port 48 exceeds the predetermined limit' this: excess: pressure is: transmitted past theauxiliary valveq 56; the: piston-portion 55 andth'e rod 55into the pilotvalv chamber 54 .and'tothe pilot valve:5l,

thuscausing downward displacement ofztheilats ter. When: the: pilot2 valve= 51.1 opens, :the auxiliary:

valve 56 closes, and from now on transmits the pressure prevailing in the utilization port 48 to the spring 53, thus keeping the pilot valve open as long as this pressure exceeds the predetermined maximum. The opening of the pilot valve 5! permits the outflow of pressure fluid from the plunger chamber 52, and a consequent opening of the valve 5| under the pressure existing in the inlet port 46. When the valve 5| opens the pressure in the inlet port 46 drops and the check valve 49 closes. Thus, regardless of pressure variations in the inlet port 46, the pilot valve 51 will remain open until the pressure in the utilization port 48 and in the line connected therewith falls below the predetermined limit.

In Fig. 2, the casing has a supply port 66, a return port 61, and a utilization port 68. The principal valve means include a seat 69, a main valve body 10, including the plunger portion 10, a plunger chamber H, and a spring 12. A check valve 13 controlled by a spring 13 prevents back flow from port 68 into supply port 66.

The pilot valve means include a pilot valve seat I4 formed in the main valve body 14, and a pilot ball valve 15 loaded by a spring 89. A rod 11 extends axially through the main valve 10 and plunger chamber I I, and passes slidably through an axial bore 16 in the stem of the check valve 13. A spring pressed ball 18 is seated on the upper end of the rod 11. The plunger chamber 1| communicates with the inlet port 66 through leak passage 19 surrounding the stem of the check valve 13. The operation of the valve according to Fig. 2 in which the pilot pressure room is practically identical with the plunger chamber II is in all essential similar to that of the valve shown in Fig. 1, with the exception that in the valve according t Fig. 2, the pressure fluid passes directly from the inlet port 66 through the passage 19 into the plunger chamber 1 l, and this passage 19 is not closed when the pilot valve 15 opens.

I claim:

An unloader valve comprising a valve casing provided with an inlet port, a utilization port, and an exhaust port, a check valve between said inlet and utilization ports to open and to permit the flow of pressure fluid from said inlet port to said utilization port at a pressure below a predetermined unloading pressure, a main valve including a valve seat between said inlet and exhaust ports and a valve body normally urged upon said seat from the inlet side thereof and acted upon by the pressure prevailing in said inlet port in the direction of opening said valve, a plunger chamber provided in said valve casing coaxially with said valve seat, a plunger element forming an integral part of said valve body and fitting slidably in said plunger chamber, said plunger element being acted upon by the pressure prevailing in said plunger chamber to oppose opening of said valve, a tubular pilot valve chamber provided in said valve casing and opening at one end thereof into said utilization port rearwardly 01' said check valve and at its other end into a space in communication with said exhaust port, a pilot valve seat formed at said other end of said pilot valve chamber, a pilot valve cooperating with said pilot valve seat to close said pilot valve chamber from the outside, a spring holding'said pilot valve on its seat unless the pressure in said pilot valve chamber exceeds said predetermined unloading pressure, an auxiliary valve seat at said first end of said pilot valve chamber, an elongated rod traversing said pilot valve chamber in axial direction with at least a slight clearance adjacent said first end and with considerable clearance at the other end of said pilot valve chamber, one end of said rod resting against said pilot valve and its other end projecting, in closed position of said pilot valve, from said first end of said pilot valve chamber and supporting an auxiliary valve body adapted to cooperate with said auxiliary valve seat when said pilot valve opens and to transmit to said spring the pressure prevailing in said utilization port regardless of the pressure drop resulting in said pilot valve chamber from the opening of said pilot valve, and a restricted passage connecting said plunger chamber with the part of said pilot valve chamber traversed with considerable clearance by said rod.

JEAN MERCIER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 221,194 Scovell Nov. 4, 1879 534,514 Mellin Feb. 19, 1895 738,161 Christensen Sept. 8, 1903 1,056,562 Lombard Mar. 18, 1913 1,110,567 McAulay Sept. 15, 1914 1,991,227 Proctor Feb. 12, 1935 2,114,760 Briggs Apr. 19, 1938 2,397,117 Ashton Mar. 26, 1946 2,404,102 Schultz July 16, 1946 2,447,820 Schultz Aug. 24, 1948 FOREIGN PATENTS Number Country Date Germany of 1880 

